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Animals : an open access journal from MDPI2022; 12(22); 3093; doi: 10.3390/ani12223093

Evaluation of Strategies to Reduce Equine Strongyle Infective Larvae on Pasture and Study of Larval Migration and Overwintering in a Nordic Climate.

Abstract: Horses, as grazing animals, are inadvertently exposed to intestinal parasites that, if not controlled, may cause disease. However, the indiscriminate use of anthelmintic drugs has led to drug resistance, highlighting the need for pasture-management practices to reduce the level of parasitic exposure and lessen reliance on drugs. The efficacy of such methods depends both on the epidemiology of the parasites and the prevailing weather conditions. The aim of the study was to investigate the effect of faecal removal and harrowing on reducing the number of parasite larvae in herbage. Moreover, the migratory and survival ability of strongyle larvae in a Nordic climate was studied. Faeces from horses naturally infected with strongyle nematodes were used to contaminate pastures and grass samples were collected to harvest larvae. Twice-weekly faecal removal significantly reduced larval yields, whereas harrowing on a single occasion under dry weather conditions in the summer did not. Strongyle larvae were able to migrate 150 cm from the faecal pats, but most larvae were found within 50 cm. Both Cyathostominae and survived the winter months with larvae harvested up to 17-18 months after faecal placement. Resting of pastures for one year greatly reduced the parasite level, but two years of rest were required for parasite-free pasture.
Publication Date: 2022-11-10 PubMed ID: 36428321PubMed Central: PMC9686517DOI: 10.3390/ani12223093Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research investigated methods for reducing parasitic larvae in horse pastures, focusing on fecal removal and harrowing. It also studied the survival abilities of strongyle parasites in a Nordic climate, finding that these larvae could survive long periods and migrate significant distances from fecal deposits.

Research Objective

  • The main aim of this study was to explore effective methods for controlling exposure of horses to strongyle parasites in the pasture. This includes examining the effectiveness of fecal removal and harrowing in reducing the number of parasite larvae in herbage.
  • The research also sought to learn more about the survival and migration patterns of strongyle larvae in a Nordic climate, which is vital information for implementing effective pasture management strategies.

Methodology

  • The researchers used feces from horses naturally infected with strongyle nematodes to contaminate pastures. This natural contamination provided a realistic environment to study effective control methods.
  • Grass samples from these pastures were collected to harvest larvae, allowing scientists to examine their migration patterns and survival abilities.

Key Findings

  • Twice-weekly fecal removal significantly reduced the amount of parasitic larvae in the pastures. This shows that regular removal of horse feces can be an effective strategy in controlling parasites.
  • Strongyle larvae were found to be able to survive long periods — up to 17-18 months after fecal placement — and could migrate up to 150 cm from the fecal pats. However, most larvae were found within 50 cm of the feces. This indicates the persistence and resilience of these parasites under Nordic climate conditions.
  • Single harrowing under dry conditions in the summer did not significantly reduce larval yield. This suggests that this practice alone may not be a sufficient control method.
  • A period of one year of pasture rest greatly reduced the parasite level, but a two-year rest was required for a parasite-free pasture. This could aid in planning rotational pasture use in horse farms to minimize the parasite burden.

Cite This Article

APA
Osterman-Lind E, Hedberg Alm Y, Hassler H, Wilderoth H, Thorolfson H, Tydén E. (2022). Evaluation of Strategies to Reduce Equine Strongyle Infective Larvae on Pasture and Study of Larval Migration and Overwintering in a Nordic Climate. Animals (Basel), 12(22), 3093. https://doi.org/10.3390/ani12223093

Publication

ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 12
Issue: 22
PII: 3093

Researcher Affiliations

Osterman-Lind, Eva
  • Department of Microbiology, Section for Parasitology, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden.
Hedberg Alm, Ylva
  • Department of Biomedical Science and Veterinary Public Health, Parasitology Unit, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
  • Horse Clinic, University Animal Hospital, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
Hassler, Hillevi
  • Mälaren Equine Clinic AB, Hälgesta 1, SE-193 91 Sigtuna, Sweden.
Wilderoth, Hanna
  • Department of Clinical Sciences, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.
Thorolfson, Helena
  • Realgymnasiet, Trekantsvägen 3, SE-117 43 Stockholm, Sweden.
Tydén, Eva
  • Department of Biomedical Science and Veterinary Public Health, Parasitology Unit, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden.

Grant Funding

  • H-15-47-097 / Foundation for Swedish and Norwegian Equine Research

Conflict of Interest Statement

The authors declare no conflict of interest.

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